1. Field of the Invention
The present invention generally relates to a cable reel drive assembly and, more particularly, is concerned with a torque limiting slip clutch apparatus and a cable reel drive assembly employing the slip clutch apparatus.
2. Description of the Prior Art
Motor-driven constant-torque reel drive assemblies are used in various industrial applications where cables and hoses of varying lengths reeled out from a stationary source of supply are needed to provide power and control to machinery and equipment that move relative to the stationary supply source. As used hereafter, the term "cable" is meant to include within the scope of its definition electrical cables, hydraulic hoses and the like.
Well-known examples of where such reel drive assemblies are used are levelwind and monospiral cable reels commercially available from Gleason Reel Corp. of Mayville, Wis., a subsidiary of Hubbell Corporation. The levelwind and monospiral cable reels are used in conjunction with the operation of container and raw material handling cranes for unloading ships. The levelwind cable reel stores cable in, and thus pays out cable from, a side-by-side single-layer configuration of cable on the reel. The monospiral reel stores cable in, and thus pays out cable from, a single multiple-layer configuration of cable on the reel.
There are various factors which can adversely affect the operational efficiency of a cable reel drive assembly. These factors include different rotation speed and output torque requirements during cable payout as opposed to cable rewind and the inertia effects of various components on cable tension during cable payout in response to machinery accelerations. Consequently, a need still remains for innovations to a cable reel drive assembly which will give due consideration to these factors and thereby reduce their adverse impact on operational efficiency of the cable reel drive assembly.